In October, The Times spoke to some experts in acoustics who suggested the sonic weapon theory was “more appropriate to a James Bond movie”.

Stranger still, in December, doctors who were treating the US Embassy staff discovered abnormalities in the white matter of the victim’s brains. From The Associated Press:

Loud, mysterious sounds followed by hearing loss and ear-ringing had led investigators to suspect “sonic attacks.” But officials are now carefully avoiding that term. The sounds may have been the byproduct of something else that caused damage, said three US officials briefed on the investigation. They weren’t authorized to discuss it publicly and demanded anonymity.

Physicians, FBI investigators and US intelligence agencies have spent months trying to piece together the puzzle in Havana, where the US says 24 US government officials and spouses fell ill starting last year in homes and later in some hotels.

Doctors still don’t know how victims ended up with the white matter changes, nor how exactly those changes might relate to their symptoms. US officials wouldn’t say whether the changes were found in all 24 patients.

But acoustic waves have never been shown to alter the brain’s white matter tracts, said Elisa Konofagou, a biomedical engineering professor at Columbia University who is not involved in the government’s investigation.